A checklist for assessing the methodological quality of concurrent tES-fMRI studies (ContES checklist): a consensus study and statement

Abstract

Low-intensity transcranial electrical stimulation (tES), including alternating or direct current stimulation, applies weak electrical stimulation to modulate the activity of brain circuits. Integration of tES with concurrent functional MRI (fMRI) allows for the mapping of neural activity during neuromodulation, supporting causal studies of both brain function and tES effects. Methodological aspects of tES-fMRI studies underpin the results, and reporting them in appropriate detail is required for reproducibility and interpretability. Despite the growing number of published reports, there are no consensus-based checklists for disclosing methodological details of concurrent tES-fMRI studies. The objective of this work was to develop a consensus-based checklist of reporting standards for concurrent tES-fMRI studies to support methodological rigor, transparency and reproducibility (ContES checklist). A two-phase Delphi consensus process was conducted by a steering committee (SC) of 13 members and 49 expert panelists through the International Network of the tES-fMRI Consortium. The process began with a circulation of a preliminary checklist of essential items and additional recommendations, developed by the SC on the basis of a systematic review of 57 concurrent tES-fMRI studies. Contributors were then invited to suggest revisions or additions to the initial checklist. After the revision phase, contributors rated the importance of the 17 essential items and 42 additional recommendations in the final checklist. The state of methodological transparency within the 57 reviewed concurrent tES-fMRI studies was then assessed by using the checklist. Experts refined the checklist through the revision and rating phases, leading to a checklist with three categories of essential items and additional recommendations: (i) technological factors, (ii) safety and noise tests and (iii) methodological factors. The level of reporting of checklist items varied among the 57 concurrent tES-fMRI papers, ranging from 24% to 76%. On average, 53% of checklist items were reported in a given article. In conclusion, use of the ContES checklist is expected to enhance the methodological reporting quality of future concurrent tES-fMRI studies and increase methodological transparency and reproducibility.

Digitalized transcranial electrical stimulation: A consensus statement

“…We used a Delphi technique, in which comments and feedback are iteratively discussed (Hsu and Sandford, 2019), for addressing challenges and proposing recommendations for digitizing tES trials. Following recent papers (Ekhtiari et al, 2022a(Ekhtiari et al, , 2022b, we initially convened a steering committee (SC) group, formed based on the collaborative network of the leading authors, to develop structured questionnaires with items using Five-point Likert scales or open questions (Supplementary Material -Appendix 2). The SC also provided qualitative feedback on several topics that were analyzed by the leading authors and qualitatively described here.…”

Dose-Response Transcranial Electrical Stimulation Study Design: A Well-Controlled Adaptive Seamless Bayesian Method to Illuminate Negative Valence Role in Tinnitus Perception

“…Further validation, particularly under the systematic procedure of simultaneous tES-fMRI (Ekhtiari et al, 2022 ) of the proposed methodology, is suggested in future studies.…”

Human-In-The-Loop Optimization of Transcranial Electrical Stimulation Effects: A Computational Perspective Based on Systems Analysis

“…Therefore, we investigated an open-source fMRI-tDCS dataset [53] that used a TR=3.36sec and captured 0.052-0.145 Hz associated with smooth muscle cell activity, including 'initial dip' that is postulated via norepinephrine receptors on the pial arterial SMCs [14,15] that can modulate hemodynamics (from arterioles as they transition into capillaries). Ekhtiari and colleagues [54] recently published a checklist for assessing the methodological quality of concurrent transcranial electrical stimulation (tES)-functional magnetic resonance imaging (fMRI) studies; however, the protocol did not elaborate on the methods for separating tES effect on the neuronal activation from the effect on the neurovascular coupling [9], i.e., the hemodynamic response function (HRF). Here, mapping of the tES stimulus-related Blood Oxygen Level Dependent (BOLD) signals measured using fMRI is usually achieved by fitting a general linear model (GLM) to the time course with a pre-specified canonical HRF model, e.g., double-gamma function [55].…”